Recently, imaging devices, such as digital still cameras and digital video cameras, are capable of improving the quality of output images by increasing the number of pixels constituting an image sensor incorporated therein. On the other hand, as another method for enabling an imaging device to output high-quality images, it is desired that the imaging device has a camera-shake correction mechanism for compensating blur of a shooting subject that may be caused when a hand of a user who holds the imaging device shakes.
More specifically, the imaging device is equipped with a detection element, such as a gyro sensor, and is configured to drive an optical component, such as a lens or an image sensor, according to an angular speed component that is caused by the vibration of the imaging device so as to compensate the blur of the shooting subject. Accordingly, even in a state where the imaging device vibrates, an acquired video signal does not include any influence caused by a vibration component. Thus, a high-quality video signal free from image blur can be acquired.
FIG. 13 illustrates a configuration of an imaging device that includes a camera-shake correction driving mechanism using a stepping motor (refer to Japanese Patent Application Laid-Open No. 2006-208873). According to the configuration illustrated in FIG. 13, an X gyro 10 and a Y gyro 12 detect angular speeds of the imaging device that is vibrating. A CPU 14 converts the angular speeds detected by the X gyro 10 and the Y gyro 12 into angular information representing a moving amount of the imaging device. Then, the CPU 14 generates motor driving pulses (i.e., a stepping motor control signal) according to the angular information and outputs the generated motor driving pulses to a motor driver 16. The motor driver 16 generates coil current according to the motor driving pulses to drive a stepping motor 18. An optical component or an image sensor is connected to the stepping motor 18. The driving of the stepping motor 18 can correct the position of the optical component or the image sensor so as to compensate a movement caused by the vibrating imaging device.
A camera-shake correction mechanism using a stepping motor is useful in that the number of components provided in the imaging device is relatively small, compared to a mechanism using a voice coil motor or any other motor. In a case where a voice coil motor is used, the imaging device requires a hall element capable of detecting the position of an optical component (such as a lens) and a signal processing circuit that can process an output signal of the hall element. In a case where a stepping motor is used, the imaging device is not required to include the above-described hall element and the signal processing circuit. Therefore, the cost of the imaging device can be reduced. Further, the stepping motor based camera-shake correction mechanism is different from the voice coil motor based mechanism in the configuration of parts or components and is, therefore, different in the configuration of a control circuit that performs a motor driving control.